Dear Chris,  I worked in the laboratory of M. Grumbacher (the artist's
paint manufacturer), for about ten years before I committed myself to
natural science illustration.  During that time we experimented extensively
with accelerated aging tests on acrylics and oil paints in our Atlas
Xenon-lab fadometer. I found that a typical product, like the old Hyplar
Hygel, a high visosity clear jelled acrylic emulsion resin, showed
virtually no discoloration after long exposures to high light levels and
other weathering conditions.  Upon drying the acrylic resion is essentially
neutral and dosen't produce acidic decomposition products.  So, I
personally believe this type of material is archival.  Its high viscosity
should also produce far less warpage than the more liquidy Elmer's Glue
(which I think is a vinyl acetate preparation).  I unfortunately don't
remember what I heard about from external sources regarding the archival
potential of acrylics as glues, so you will have to check with paper
conservators directly for their expert opinions.  I don't know whether
Grumbacher is still manufacturing acrylics.  I left there ten years ago and
they have been sold and bought a number of times since then.  Kohi-noor
might be the most recent owner.  They're out in New Jersey and you might be
able to track them down.  I remember using a rubber breyer to smooth out
paper which had Hygel applied to the back surface.  The results were fine.
 Lastly, there is a company in Rochester, N.Y. called Light Impressions
which carries a large line of archival materials for both photographic and
graphic arts usage.  Their number is 1-800-828-5539.  Hope this helps.
Mike Rothman